PE,
This may be why the emulsion is prone to bubble upon drying, if the wet film thickness is too thick. Partcles can create bubbles. Prior to very recently, I relied on the tape thickness on the ends of my puddle pusher to controle wet film thickness. Then I purchased a wet film gauge. I found that my wet film thickness was actualy 12-14 mils, not the 7-8 mils that I had presumed. Reducing film thickness to 7-8 mils got rid of the bubbles, so far.
I will make the higher speed emulsion today, coat this afternoon and have more plates to show you tomorrow.
Bill